Ben Johnson has returned to Seoul's Olympic Stadium, 25 years to the day of the steroid-assisted 100-metres final victory that destroyed his athletic career and reputation.
In the biggest scandal to hit the Olympics, the Canadian sprinter was stripped of his gold medal and world record 9.79 seconds time after testing positive for banned steroids at the 1988 Seoul Games.
However only two of the runners in that final remained untainted, and it later emerged that eventual gold medallist Carl Lewis also tested positive for stimulants at the US Olympic trials earlier that year.
Johnson's now an anti-doping ambassador and wants to help eliminate drugs in sport.
He says do it naturally and if you don't make it, you don't make it but at least you tried to do it naturally.
Johnson says there are many athletes who have tested positive and they are left alone, but his organisation is here to help them rehabilitate.
Despite the huge controversy from that 1988 race, it took a further 11 years for the World Anti Doping Agency to be founded in 1999.
